Generating scene-aware audio using a neural network-based acoustic analysis

ABSTRACT

Methods, systems, and non-transitory computer readable storage media are disclosed for rendering scene-aware audio based on acoustic properties of a user environment. For example, the disclosed system can use neural networks to analyze an audio recording to predict environment equalizations and reverberation decay times of the user environment without using a captured impulse response of the user environment. Additionally, the disclosed system can use the predicted reverberation decay times with an audio simulation of the user environment to optimize material parameters for the user environment. The disclosed system can then generate an audio sample that includes scene-aware acoustic properties based on the predicted environment equalizations, material parameters, and an environment geometry of the user environment. Furthermore, the disclosed system can augment training data for training the neural networks using frequency-dependent equalization information associated with measured and synthetic impulse responses.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.16/189,866, filed on Nov. 5, 2019. The aforementioned application ishereby incorporated by reference in its entirety.

BACKGROUND

Improvements to computer processing technologies have led to a recentincrease in augmented and virtual reality applications. For example,many digital media systems utilize virtual or augmented reality toenhance various computing environments including educationalapplications, commercial applications, professional applications, andentertainment applications. Implementing virtual and augmented realityinto such computing environments can improve interactivity, immersion,accuracy, and enjoyability of an experience. For example, someconventional systems can generate sounds within an augmented realityenvironment by re-producing digital audio from other user devices.

SUMMARY

One or more embodiments provide benefits and/or solve one or more of theforegoing or other problems in the art with systems, methods, andnon-transitory computer readable storage media that render scene-awareaudio in virtual/augmented reality environments using neuralnetwork-based acoustic analysis. To illustrate, the disclosed systemscan provide an audio rendering of a digital character via an augmentedreality device, such that the audio rendering accurately mimics theacoustic properties of the room and a virtual location of the digitalcharacter within the room. For example, in one or more embodiments, thedisclosed systems utilize neural networks to predict acoustic propertiesof a user environment (e.g., a T60 value and an equalization frequencyfilter applicable to a room) based on an audio recording (e.g., anon-impulse response recording) captured within the user environment.The disclosed systems can use the acoustic properties of the userenvironment to determine material parameters of the user environment viaan audio simulation. The disclosed systems can then use the acousticproperties and material parameters to generate a scene-aware audiosample for presentation within a virtual or augmented realityenvironment based on a user's surrounding environment.

Furthermore, in one or more embodiments, the disclosed systems canaugment a training dataset of impulse responses for improved training ofthe neural networks. For instance, the disclosed systems can fitequalizations of measured impulse responses to normal distributions andrandomly sample equalizations from the normal distributions. Thedisclosed systems can generate filters by comparing the randomly sampledequalizations to equalizations of existing impulse responses (e.g.,synthetic impulse responses). The disclosed systems can then extend thetraining dataset by generating new impulse responses using the filtersgenerated from the randomly sampled equalizations. The disclosed systemscan thus improve the efficiency, accuracy, and flexibility of computingdevices that render audio within virtual/augmented reality environmentsaccording to a user's environment.

Additional features and advantages of one or more embodiments of thepresent disclosure will be set forth in the description below.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments will be described and explained with additionalspecificity and detail through the use of the accompanying drawings inwhich:

FIG. 1 illustrates an example system in which an audio rendering systemcan operate in accordance with one or more implementations;

FIG. 2 illustrates a diagram of an overview of a process for renderingscene-aware audio in accordance with one or more implementations;

FIG. 3 illustrates a diagram of a detailed view of a process forrendering scene-aware audio in accordance with one or moreimplementations;

FIG. 4 illustrates a flowchart of a process for using neural networks togenerate a scene-aware audio sample in accordance with one or moreimplementations;

FIG. 5 illustrates chart diagrams of energy curves for a plurality offrequency bands in accordance with one or more implementations;

FIG. 6 illustrates a flowchart of a process for augmenting a trainingdataset with synthetic impulse responses in accordance with one or moreimplementations;

FIG. 7 illustrates a diagram of an embodiment of a neural networkstructure for predicting acoustic properties of an environment inaccordance with one or more implementations;

FIGS. 8A-8D illustrate diagrams of impulse response equalizations anddistributions in accordance with one or more implementations;

FIG. 9 illustrates a diagram of plotted results of a user ratings testbased on rendered audio using different methods in accordance with oneor more implementations;

FIG. 10 illustrates a diagram of the audio rendering system of FIG. 1 inaccordance with one or more implementations;

FIG. 11 illustrates a flowchart of a series of acts for generatingscene-aware audio samples using neural networks in accordance with oneor more implementations;

FIG. 12 illustrates a block diagram of an exemplary computing device inaccordance with one or more embodiments.

DETAILED DESCRIPTION

One or more embodiments of the present disclosure include an audiorendering system that utilizes neural networks to predict acousticproperties of a user environment for rendering scene-aware audio withinthe user environment. In particular, the audio rendering system canavoid the complex and cumbersome testing procedures required to obtainan impulse response by utilizing an unobtrusive approach that works onin-situ speech recordings and video signals captured via commoditydevices. For example, the audio rendering system can use neural networksto predict frequency-dependent environment equalizations andreverberation decay times of a user environment based on an audiorecording within the environment. Specifically, in one or moreembodiments, the audio rendering system predicts the acoustic propertiesusing the neural networks using a recording within the user environmentfrom a user device (e.g., a speech recording from a smartphonesmartphone). The audio rendering system can use the predicted acousticproperties and an audio simulation model for the user environment todetermine material parameters of the user environment. The audiorendering system can then use the material parameters and acousticproperties to generate an audio sample at a location within a virtualrepresentation of the user environment. Thus, the audio rendering systemcan efficiently, flexibly, and accurately render scene-aware audiowithin a virtualization of a user environment using speech recordingsfrom user devices and without the time-consuming and difficult processof capturing an impulse response.

For example, in one or more embodiments, the audio rendering system canidentify an audio recording captured within a user environment. Toillustrate, the audio recording can include a speech recording capturedby a user device or from a video/audio recording that was capturedwithin the user environment. Additionally, the audio rendering systemcan identify an estimated environment geometry of the user environment(e.g., by utilizing a video camera, a structure from motion algorithm,and/or an external application, device, or system). For instance, insome embodiments the estimated environment geometry includes a virtualrepresentation such as a three-dimensional rendering of the userenvironment captured by the client device or another device.

The audio rendering system can use the audio recording and the estimatedenvironment geometry to predict acoustic properties of the userenvironment. Specifically, the audio rendering system can analyze theaudio recording using machine-learning to predict environmentequalizations and reverberation decay times (e.g., a T60 value) for theuser environment. To illustrate, the audio rendering system can use afirst convolutional neural network to predict the environmentequalizations and a second convolutional neural network to predict thereverberation decay times for a number of frequency sub-bands.Additionally, in one or more embodiments, the neural networks can havesimilar structures with the exception of the output layers correspondingto the frequency sub-bands of the outputs.

In addition to predicting environment equalizations and reverberationdecay times for the user environment, the audio rendering system canestimate material properties of the user environment. In particular, theaudio rendering system can perform an audio simulation for the userenvironment based on the identified estimated environment geometry. Theaudio rendering system can then adjust an energy curve for the audiosimulation based on an energy curve corresponding to the predictedreverberation decay times for the user environment. Specifically, theaudio rendering system can optimize material parameters utilizing anobjective function that seeks to align a slope of the simulation energycurve to match (or be similar to) a target slope associated with thereverberation energy curve. The audio rendering system can thus optimizethe material parameters (e.g., material absorption coefficients) at thesame frequency sub-bands as the reverberation decay times to accuratelydetermine the materials of the user environment.

Using the estimated material parameters and the predicted environmentequalizations, the audio rendering system can then generate an audiosample that includes scene-aware information based on the userenvironment. For instance, the audio rendering system can modify apre-recorded audio sample by applying an equalization filter based onthe environment equalizations to the pre-recorded audio sample.Additionally, the audio rendering system can apply the environmentmaterial parameters to the pre-recorded audio sample such that themodified audio sample has an energy curve that reflects thereverberation decay times of the user environment. The audio renderingsystem can then process the generated/modified audio sample to place theaudio sample at a specific location within the virtual representation ofthe user environment. The audio rendering system can thus provide audiothat sounds as if the audio is occurring within the user environment.

In one or more embodiments, the audio rendering system can also augmenta training dataset used to train the neural network(s) that predictacoustic properties of the user environment. In particular, the audiorendering system can use a training dataset including at least somemeasured impulse responses corresponding to a variety of userenvironments. The audio rendering system can fit equalization gains ofthe measured impulse responses to normal distributions and then randomlysample from the normal distributions. For instance, the audio renderingsystem can randomly sample from normal distributions corresponding toeach of a set of frequency sub-bands to obtain a set of sampled valuesacross the frequency sub-bands. The audio rendering system can alsocompare the sampled values to equalizations of a set of impulseresponses (e.g., synthetic impulse responses) and then generatefrequency filters to apply to the impulse responses and generate newsynthetic impulse responses. By augmenting the training dataset in thismanner, the audio rendering system can extend the training dataset toinclude more impulse responses, and therefore, improve the performanceof the neural networks.

Conventional systems that render audio in virtual/augmented realityenvironments have a number of shortcomings in relation to efficiency,flexibility, and accuracy of operation. Specifically, to produce anaccurate audio rendering that matches a target environment in which auser is located, some conventional systems require impulse responsescaptured within the user environment. Capturing impulse responses can betime-consuming and difficult due to using special recording hardware inspecific conditions for recording the impulse responses. Additionally,if the position of either the source or listener of virtual/augmentedaudio changes within the user environment, these conventional systemsmust re-capture impulse responses, which is very inefficient.

Furthermore, conventional systems that rely on captured impulseresponses for accurately rendering audio that reflects a targetenvironment are also inflexible. In particular, because of theinefficiencies and difficulties involved with capturing impulseresponses, the conventional systems are not useful for interactiveapplications that require (or allow) user movement within a userenvironment. Indeed, as a user moves within the user environment,recording additional impulse responses corresponding to the movement isnot feasible in real-time, and introduces significant difficulty andtime if done in advance.

Some conventional systems may not rely on impulse responses to renderaudio within a virtual or augmented reality environment and are thusinaccurate and inflexible. Instead, such conventional systems usesynthetic environments and pre-determined/known acoustic properties ofthe synthetic environments for rendering audio. Because the renderedaudio incorporates acoustic properties of the synthetic environments,the conventional systems produce audio that does not match the userenvironment in which a user experiencing the virtual/augmented realityenvironment is located. Rendered audio that does not match properties ofa user environment results in degraded immersion and sense of presencefor the user.

The disclosed audio rendering system can provide a number of advantagesover conventional systems. For example, the audio rendering system canimprove the efficiency, flexibility, and accuracy of computing systemsthat render audio within virtual or augmented reality environments. Forinstance, in contrast to conventional systems that rely on very limitedsets of explicitly measured impulse responses, by using neural networksto predict environment acoustic properties based on simple audiorecordings (e.g., speech recordings) using commodity devices (e.g.,smartphones), the audio rendering system can generate accurate audiosamples that reflect the properties of a user's current environmentwithout needing an impulse response for the user environment. Inaddition, by using a unique objective function that focuses on aligningslope of an energy decay curve to a predicted reverberation decay time,the audio rendering system can perform optimization routines twice asfast as conventional systems. The audio rendering system can thusimprove the efficiency of computing devices implementing virtual oraugmented reality environments.

In addition to improving efficiency, the audio rendering system canimprove the flexibility of computing devices implementingvirtual/augmented reality environments. In particular, by eliminatingthe need to capture impulse responses and using neural networks toanalyze simple audio recordings, the audio rendering system can providescene-aware audio rendering for any user environment. To illustrate,because the only device needed is a computing device capable ofcapturing audio (e.g., speech), the audio rendering system can thereforepredict the acoustic properties of a user environment quickly andefficiently and expand the feasible implementation of scene-aware audiorendering to any user environment without the use of special equipmentor environment configurations. In addition, the audio rendering systemcan flexibly predict environment equalization and reverberation decayrates across a variety of different frequency sub-bands (in contrast toconventional systems that identify acoustic properties from impulseresponses for full-band frequencies).

The audio rendering system also improves the accuracy of computingdevices rendering audio for virtual/augmented reality environments. Asan initial matter, the audio rendering system is the first to predictimpulse response equalization from raw speech data (e.g., utilizing anequalization neural network). Moreover, the audio rendering system isable to accurately generate audio samples that reflect the acousticproperties of a user environment by using neural networks that predictthe environment's acoustic properties. Indeed, the audio renderingsystem is not limited to generating audio samples for synthetic virtualenvironments, but rather is able to accurately portray sound that is notperceptually different from other sounds within a user environment.

In short, unlike all previous systems that require a clean impulseresponse recording for accurate estimation and optimization of boundarymaterials, the audio rendering system can infer material parameters, T60values, and equalization from raw speech signals using a neural networkmodel (e.g., a convolutional neural network).

As illustrated by the foregoing discussion, the present disclosureutilizes a variety of terms to describe features and advantages of theaudio rendering system. Additional detail is now provided regarding themeaning of such terms. For example, as used herein, the term “neuralnetwork” refers to a computer representation that can be tuned (e.g.,trained) based on inputs to approximate unknown functions. Inparticular, the term “neural network” can include a machine-learningmodel that utilizes algorithms to learn from, and make predictions on,known data by analyzing the known data to learn to generate outputs thatreflect patterns and attributes of the known data. For instance, aneural network can include, but is not limited to, a convolutionalneural network, a recurrent neural network, a generative adversarialneural network, or a graph neural network. A neural network makeshigh-level abstractions in data by generating data-driven predictions ordecisions from the known input data. In one or more examples, a neuralnetwork can include, or be included in, a deep learning model thatanalyzes digital audio to generate predictions of acoustic properties ofa user environment such as environment equalizations and reverberationdecay times.

As used herein, the term “user environment” refers to a physicalenvironment in which a user is located. For example, a user environmentcan include a room or other enclosed space in which a user is located.In additional embodiments a user environment can include a partiallyenclosed space or an open space. A user environment can also include avirtual reality environment, such as a virtual room or virtual space inwhich a user or avatar is located. As described herein, the audiorendering system can obtain information associated with a userenvironment (e.g., audio recording and environment geometry) to use ingenerating audio samples to be provided to a user client device withinthe user environment, such as within a virtual/augmented realityapplication in the user environment.

As used herein, the term “estimated environment geometry” refers to adigital representation of a user environment. In particular, anestimated environment geometry can include a digital environment ormodel that a computing device generates to represent a physicalenvironment. In one or more embodiments, a computing device can generatean estimated environment geometry by analyzing video of a userenvironment (e.g., video captured by the computing device or by anothercomputing device including a video capture device) and thenreconstructing the user environment by determining dimensions, surfaces,and objects of the user environment. In additional embodiments, a systemor user (e.g., a building architect associated with the environment) canprovide manually measured geometry for the environment.

As used herein, the term “audio recording” refers to digital audio. Forexample, an audio recording can include a digital capture of speechoccurring within a user environment. To illustrate a client device cancapture audio within a user environment by using an audio capture device(e.g., a microphone) and software that generates an audio file forstoring on the client device and/or providing to the audio renderingsystem for analysis using a neural network.

As used herein, the term “environment equalization” refers to amodification or alteration of an audio frequency energy amplitudecorresponding to a user environment. For instance, an environmentalequalization can include a frequency filter that reflects the resonancesor diffraction effects of a room (e.g., a linear finite impulse responseequalization filter). In particular, an environment equalization canindicate how a user environment relatively strengthens (e.g., boosts) orweakens (e.g., cuts) the energy of a specific frequency sub-band (orfrequency range). For example, an environment equalization can indicatewave effects (e.g., relative modifications to particular frequencysub-bands) that geometric acoustic simulation algorithms may not takeinto account. Additionally, a user environment can affect the energy ofaudio differently at different frequency sub-bands. Accordingly, theaudio rendering system can determine a plurality of frequency-dependent(or frequency-specific) environment equalizations across a plurality offrequency sub-bands (e.g., an equalization for each sub-band). Also asused herein, the term “frequency sub-band” refers to a subset of audiofrequencies centered at a specific frequency. To illustrate a frequencysub-band can correspond to a subset of frequencies centered at 125 Hz,1000 Hz, or 4000 Hz, etc., and covering a range of frequencies on bothsides of the center frequency.

As used herein, the term “reverberation decay time” refers to ameasurement that indicates the amount of time it takes for sound todecay a specified number of decibels below the original sound based on auser environment. For instance, a reverberation decay time can refer toa T60 measurement that indicates the amount of time (in seconds) ittakes for sound to decay 60 dB. In other examples, a reverberation decaytime can indicate the amount of time it takes for sound to decay anotheramount of decibels (e.g., 20 dB or 30 dB). Reverberation decay time mayalso correspond to a specific frequency sub-band, such that eachfrequency sub-band has a separate reverberation decay time for the userenvironment. Accordingly, the audio rendering system can also generatefrequency-dependent (or frequency sub-band specific) reverberation decaytimes across a plurality of frequency sub-bands.

As used herein, the term “environment material parameter” refers to ametric indicating a property of a material of an object or surface thataffects sound within a user environment. Specifically, an environmentmaterial parameter can include a material absorption coefficient thataffects a reverberation decay time of sound within a user environment.For example, each object or surface can have a material with a specificmaterial absorption coefficient that determines how much energy theobject or surface absorbs over time. To illustrate, materials with highabsorption rates can significantly impact the reverberation decay ratesof the user environment as a whole.

As used herein, the term “audio sample” refers to a digital audio clip.For instance, an audio sample can include audio that the audio renderingsystem plays on a client device within a user environment. In one ormore embodiments, the audio rendering system can generate an audiosample by modifying a pre-recorded or previously generated audio clipbased on acoustic properties extracted for a user environment.Additionally, an audio sample can include new audio that the audiorendering system generates using a set of audio creation tools havingcertain acoustic properties to simulate sound in a user environment.

Additional detail will now be provided regarding the audio renderingsystem in relation to illustrative figures portraying exemplaryimplementations. To illustrate, FIG. 1 includes an embodiment of asystem environment 100 in which an audio rendering system 102 operates.In particular, the system environment 100 includes server device(s) 104and a client device 106 in communication via a network 108. Moreover, asshown, the server device(s) 104 includes a virtual environment system110 including the audio rendering system 102. The audio rendering system102 can further include neural network(s) 112. Additionally, the clientdevice 106 can include a client application 114.

As shown in FIG. 1, the server device(s) 104 include the virtualenvironment system 110. The virtual environment system 110 can include,or be part of, one or more systems that implement virtual or augmentedreality environments for one or more computing applications. Forexample, the virtual environment system 110 can implementvirtual/augmented reality environments for presentation at variousclient devices (e.g., client device 106) including virtualized audio andvisual media (e.g., video or images). To illustrate, the virtualenvironment system 110 can perform operations for implementing a virtualreality environment at a virtual reality device such as a virtualreality headset. Additionally, the virtual environment system 110 canperform operations for implementing an augmented reality environment atan augmented reality device such as an augmented reality headset orother user device capable of using augmented reality (e.g., smartphone,desktop, laptop, or tablet).

In connection with implementing virtual or augmented realityenvironments, the virtual environment system 110 can receive data fromthe client device 106 via the network 108 to use in establishing avirtual/augmented reality environment. For example, the client device106 can provide information about a user environment in which the clientdevice 106 is located (or will be located for a virtual/augmentedreality presentation). In one or more embodiments, the client device 106provides an audio recording and an estimated environment geometry to thevirtual environment system 110 for implementing the virtual/augmentedreality environment on the client device 106 or on another clientdevice.

In response to receiving the data from the client device 106, thevirtual environment system 110 can provide the received data to theaudio rendering system 102 for rendering audio within thevirtual/augmented reality environment. Specifically, the audio renderingsystem 102 can process the received data using the neural network(s) 112to predict acoustic properties of the user environment. Additionally,the audio rendering system 102 can perform an audio simulation based onthe user environment to optimize estimated properties of materials inthe user environment. Based on the output(s) of the neural network(s)112, the optimized material properties, and the estimated environmentalgeometry, the audio rendering system 102 can render audio for presentingwithin the user environment that sounds like it originated in the userenvironment.

The virtual environment system 110 can also incorporate additional mediawith rendered audio in a virtual/augmented reality environment. Forinstance, the virtual environment system 110 can generate or accessvisual media such as video or images (including images of text) toinclude with rendered audio. The virtual environment system 110 can thencombine visual media with rendered audio to create a virtual/augmentedenvironment and then provide the resulting data to the client device 106for the client device 106 to present using the client application 114.

In one or more embodiments, the server device(s) 104 include a varietyof computing devices, including those described below with reference toFIG. 12. For example, the server device(s) 104 can include one or moreservers for storing and processing data associated withvirtual/augmented reality applications. The server device(s) 104 canalso include a plurality of computing devices in communication with eachother, such as in a distributed storage environment. Furthermore, theserver device(s) 104 can include devices and/or components in connectionwith one or more neural network(s) 112 and training data for trainingthe neural networks. In some embodiments, the server device(s) 104comprise a content server. The server device(s) 104 can also comprise anapplication server, a communication server, a web-hosting server, asocial networking server, a digital content campaign server, or adigital communication management server.

As mentioned, the server device(s) 104 can include components associatedwith neural networks and training data for training the neuralnetwork(s) 112. In one or more embodiments, the server device(s) 104(e.g., the audio rendering system 102 or another system) train theneural network(s) 112 using impulse responses captured within a varietyof environments. The server device(s) 104 can also train the neuralnetwork(s) 112 using synthetic data (e.g., synthetically generatedimpulse responses) in the training dataset or in a separate trainingdataset. In addition to utilizing one or more training datasets, theserver device(s) 104 can utilize a verification dataset and a testingdataset for verifying and testing training of the neural network(s) 112,respectively.

In addition, as shown in FIG. 1, the system environment 100 includes theclient device 106. The client device 106 can include, but is not limitedto, a mobile device (e.g., smartphone or tablet), a laptop, a desktop,including those explained below with reference to FIG. 12. Furthermore,although not shown in FIG. 1, the client device 106 can be operated by auser (e.g., a user included in, or associated with, the systemenvironment 100) to perform a variety of functions. In particular, theclient device 106 can perform functions such as, but not limited to,accessing, viewing, and interacting with a variety of digital content(e.g., digital images or audio within a virtual/augmented realityenvironment). The client device 106 can also perform functions forgenerating, capturing, or accessing data to provide to the virtualenvironment system 110 and the audio rendering system 102 in connectionwith virtual/augmented reality environments. For example, the clientdevice 106 can communicate with the server device(s) 104 via the network108 to provide information associated with audio recordings or estimatedenvironment geometries. Although FIG. 1 illustrates the systemenvironment 100 with a single client device 106, the system environment100 can include a different number of client devices.

Additionally, as shown in FIG. 1, the system environment 100 includesthe network 108. The network 108 can enable communication betweencomponents of the system environment 100. In one or more embodiments,the network 108 may include the Internet or World Wide Web.Additionally, the network 108 can include various types of networks thatuse various communication technology and protocols, such as a corporateintranet, a virtual private network (VPN), a local area network (LAN), awireless local network (WLAN), a cellular network, a wide area network(WAN), a metropolitan area network (MAN), or a combination of two ormore such networks. Indeed, the server device(s) 104 and the clientdevice 106 may communicate via the network using a variety ofcommunication platforms and technologies suitable for transporting dataand/or communication signals, including any known communicationtechnologies, devices, media, and protocols supportive of datacommunications, examples of which are described with reference to FIG.12.

Although FIG. 1 illustrates the server device(s) 104 and the clientdevice 106 communicating via the network 108, the various components ofthe systems 100 can communicate and/or interact via other methods (e.g.,the server device(s) 104 and the client device 106 can communicatedirectly). Furthermore, although FIG. 1 illustrates the audio renderingsystem 102 being implemented by a particular component and/or devicewithin the system environment 100, the audio rendering system 102 can beimplemented, in whole or in part, by other computing devices and/orcomponents in the system environment 100 (e.g., the client device 106).

As mentioned above, the audio rendering system 102 can accurately renderaudio samples with characteristics that correspond to a user environmentusing neural networks and without recording an impulse response for theuser environment. FIG. 2 illustrates, an overview of a process forrendering scene-aware audio according to a user environment 200.Specifically, FIG. 2 illustrates that the audio rendering system 102 canuse information about the user environment 200 to generate audio samplesincorporating the information about the user environment 200.

In one or more embodiments, as shown in FIG. 2, the user environment 200includes a physical location in which a client device 202 is located.For example, the user environment 200 can include an enclosed room inwhich a smartphone or other device is located. Additionally, the clientdevice 202 can include an audio input device to record audio within theuser environment 200. To illustrate, a user of the client device 202 canutilize the client device 202 to record a short clip of speech withinthe user environment 200. Alternatively, the client device 202 canobtain an audio sample within the user environment 200 via anothermethod such as from a video within the user environment 200 that alsoincludes audio.

After the client device 202 captures or obtains audio within the userenvironment 200, the audio rendering system 102 can utilize deepacoustic analysis 204 of the audio recording to obtain information aboutthe user environment 200. In particular, the audio rendering system 102can use deep learning to analyze the audio recording to predict specificacoustic properties of the user environment 200. For example, in one ormore embodiments described in more detail below, the audio renderingsystem predicts environment equalizations and reverberation decay timesof the user environment 200 using separate convolutional neural networksto analyze the audio recording.

In response to using the deep acoustic analysis 204 to predict certainacoustic properties of the user environment 200, the audio renderingsystem 102 can then use geometric sound propagation 206 in combinationwith the predicted acoustic properties of the user environment 200 togenerate plausible sound effects in a virtual model of the userenvironment 200. Specifically, the audio rendering system 102 candetermine how the materials and configuration of the user environment200 affect sound that originates within, or passes through, the userenvironment 200. For instance, the audio rendering system 102 candetermine how each surface will affect sound waves that bounce off thesurface (e.g., how much the sound is diminished by the surface). Theaudio rendering system 102 can also determine where to position an audiosource and how the audio source will sound when presented to the userwithin a virtual/augmented reality environment.

FIG. 2 also shows that the audio rendering system 102 can then present agenerated audio sample 208 having the acoustic properties determinedaccording to the deep acoustic analysis 204 and the geometric soundpropagation 206 within the user environment 200. In one or moreembodiments, the audio rendering system 102 presents (e.g., plays) theaudio sample 208 to the user within a virtual/augmented realityenvironment via the client device 202. Alternatively, the audiorendering system 102 can present the audio sample 208 within avirtual/augmented reality environment via a separate device associatedwith the user. In either case, by performing these operations, the audiorendering system 102 can make the audio sample 208 appear to originatefrom or nearby a specific location relative to the user within the userenvironment 200.

FIG. 3 illustrates a more detailed overview of a process for renderingscene-aware audio within a user environment. In particular, the audiorendering system 102 can communicate with a client device (e.g., clientdevice 202 of FIG. 2) to obtain audio-visual input 300 that the audiorendering system 102 can use in determining acoustic properties of theuser environment and in reconstructing the user environment within avirtual environment. For example, the audio rendering system 102 canidentify an audio recording 302 including digitally recorded audiowithin the user environment (e.g., a speech recording). Additionally,the audio rendering system 102 can also identify an environment geometry304 including a virtual representation of the user environment (e.g., byobtaining the environment geometry 304 from a video capture deviceutilizing a structure from motion algorithm or a third-party system).

In one or more embodiments, the audio rendering system 102 identifies adigital video (or a sequence of digital images) of a user environmentand obtains both an environment geometry and a digital recorded audiofrom the digital video. For example, in one or more embodiments, theaudio rendering system 102 utilizes a structure from motion algorithm orSLAM approach to generate a three-dimensional model (such as athree-dimensional point cloud) of an environment geometry based on asequence of digital images of the user environment. To illustrate, insome embodiments, the audio rendering system 102 utilizes the processdescribed by M. Bloesch, J. Czarnowski, R. Clark, S. Leutenegger, and A.J. Davison in Codeslam learning a compact, optimizable representationfor dense visual slam, The IEEE Conference on Computer Vision andPattern Recognition (CVPR), June 2018, which is incorporated byreference herein in its entirety. In some embodiments, the audiorendering system 102 utilizes alternate approaches, such as described byI. Bork in A comparison of room simulation software—the 2nd round robinon room acoustical computer simulation, Acta Acustica united withAcustica, 86(6):943-956 (2000), which is incorporated herein in itsentirety by reference.

As illustrated in FIG. 3, the audio rendering system 102 can use theaudio-visual input 300 to determine acoustic properties of the userenvironment using machine-learning and an audio simulation model.Specifically, in one or more embodiments, the audio rendering system 102analyzes the audio recording 302 performs an acoustic analysis of theaudio recording 302 to predict certain acoustic properties of the userenvironment. Additionally, in one or more embodiments, the audiorendering system 102 uses the environment geometry 304 in connectionwith predicted acoustic properties of the user environment from theacoustic analysis to perform material optimization of materials in theuser environment.

For example, FIG. 3 illustrates that the audio rendering system 102 usesneural network(s) 112 to analyze the audio recording 302. In one or moreembodiments, the audio rendering system 102 analyzes the audio recording302 using a reverberation convolutional neural network to predictreverberation decay times 306 for the user environment. For instance,the audio rendering system 102 can train the reverberation convolutionalneural network to predict reverberation decay times using a trainingdataset of impulse responses. The audio rendering system 102 can thusestimate reverberation decay times for the user environment based on asimple recording and without an impulse response for the userenvironment.

Furthermore, in one or more embodiments, the audio rendering system 102analyzes the audio recording using an equalization convolutional neuralnetwork to predict environment equalizations 308 for the userenvironment. To illustrate, the audio rendering system 102 can train theequalization convolutional neural network to predict environmentequalizations using a training dataset of impulse responses. Thetraining dataset of impulse responses used to train the equalizationconvolutional neural network may be the same training dataset used totrain the reverberation convolutional neural network. As with thereverberation decay times, the audio rendering system 102 can predictthe environment equalizations based on a simple recording and without animpulse response for the user environment.

Once the audio rendering system 102 has predicted reverberation decaytimes 306 for the user environment, the audio rendering system 102 canuse the predicted reverberation decay times 306 to determine materialsin the user environment. In one or more embodiments, the audio renderingsystem 102 can also use the environment equalizations 308 to determinematerials in the user environment. In particular, the audio renderingsystem 102 can utilize an inverse material optimization algorithm thatuses an audio simulator 310 and a material optimizer 312 to estimatematerial parameters for materials in the user environment. For instance,the audio rendering system 102 can use the audio simulator 310 to createan audio simulation model that attempts to reproduce the paths thataudio (e.g., sound energy waves) takes within the user environment. Theaudio rendering system 102 can also use the material optimizer 312 tooptimize the parameters of the materials in the audio simulation modelto correspond to the reverberation decay times 306 based on the audiorecording 302. The audio rendering system 102 can then determinematerial parameters 314 for the user environment according to theenvironment geometry 304.

After performing the acoustic analysis and material optimization, theaudio rendering system 102 can then generate a scene-aware audio sample316 that incorporates the data output by the acoustic analysis andmaterial optimization processes. In one or more embodiments, the audiorendering system 102 utilizes the environment equalizations 308, thematerial parameters 314, and the environment geometry 304 to generate atleast one audio sample that has similar acoustic properties to othersounds occurring within the user environment. Additionally, the audiorendering system 102 can place the scene-aware audio sample 316 at alocation within a virtual environment to make the audio sample 316appear to originate at a specific location (or pass into the userenvironment at a specific point) within the user environment. Bymatching the acoustic properties of the audio sample 316 to audiooccurring within the user environment, the audio rendering system 102can provide a virtual/augmented reality that is realistic and immersive.

FIG. 4 illustrates a flowchart of a series of acts 400 for using neuralnetworks to generate a scene-aware audio sample. Specifically, theseries of acts 400 includes operations that the audio rendering system102 performs to render scene-aware audio within a virtual or augmentedreality environment for presentation at a client device. While FIG. 4illustrates that the series of acts 400 includes a specific set andorder of operations for rendering scene-aware audio, the audio renderingsystem 102 may perform operations for rendering scene-aware audio usingadditional or fewer operations, or operations in a different order.

In one or more embodiments, FIG. 4 illustrates that the series of acts400 includes an act 402 of identifying an audio recording. As brieflydescribed previously, the audio rendering system 102 can obtain an audiorecording within a user environment from a client device (e.g., a userclient device such as a smartphone or other computing device capable ofcapturing a digital audio recording). For example, a client device of auser can record a short audio clip of speech (e.g., a four-second audioclip) and store the audio clip as an audio file.

Alternatively, the audio rendering system 102 can obtain the audiorecording from another source, such as from another device or from avideo clip captured within the user environment. To illustrate, theaudio rendering system 102 can obtain a video file (e.g., from theclient device of the user or from another device) including audio ofspeech within the user environment. The audio rendering system 102 canextract the audio from the video file and store the audio in a separateaudio file.

In one or more embodiments, before, after, or in connection withidentifying an audio recording, FIG. 4 illustrates that the series ofacts 400 includes an act 404 of identifying an environment geometry forthe user environment. For instance, the audio rendering system 102 canobtain a virtual representation of the user environment that includesinformation about the geometry of the user environment. In one or moreembodiments, the audio rendering system 102 (or a client device incommunication with the audio rendering system 102) can generate theenvironment geometry utilizing an application that analyzes camera orvideo input to create an accurate environment geometry. The environmentgeometry includes spatial information that the audio rendering system102 can use to determine relative locations of surfaces and objectswithin the user environment.

FIG. 4 illustrates that the series of acts 400 also includes an act 406of utilizing a neural network to predict environment equalizations forthe user environment. Specifically, as previously mentioned, the audiorendering system 102 can use an equalization convolutional neuralnetwork to predict environment equalizations from the audio recording.For example, the equalization convolutional neural network can outputpredictions of environment equalizations of the user environment for aset of frequency sub-bands because of the potential for differenteffects of the user environment and materials on different soundfrequencies. To illustrate, the audio rendering system 102 can generatepredicted environment equalizations for six sub-bands centered at {62.5,125, 250, 500, 2000, 4000}Hz, with each equalization being relative tothe 1 kHz sub-band. Each environment equalization can correspond to aspecific frequency sub-band indicating a strengthening or weakeningeffect that the user environment has on frequencies at the correspondingsub-band.

In one or more embodiments, the audio rendering system 102 generates anequalization filter corresponding to the predicted environmentequalizations. The audio rendering system 102 can use the equalizationfilter to generate or modify audio samples according to the environmentequalizations. Additionally, in at least some instances, the audiorendering system 102 can set sub-bands of the filter that do notcorrespond to a specific predicted equalization (e.g., sub-bands greaterthan 8000 Hz) to a specific energy value (e.g., −50 dB). This can limitthe impact of the frequencies outside the predicted range on the overallequalization filter and resulting audio samples.

Additionally, FIG. 4 illustrates that the series of acts 400 includes anact 408 of utilizing a neural network to predict reverberation decaytimes for the user environment. In particular, the audio renderingsystem 102 can use a reverberation convolutional neural network topredict reverberation decay times from the audio recording. Toillustrate, the reverberation convolutional neural network can outputpredictions of reverberation decay times of the user environment for aset of frequency sub-bands. For example, the audio rendering system 102can generate predicted reverberation decay times for seven sub-bandscentered at {125, 250, 500, 1000, 2000, 4000, 8000}Hz. The predictionsof reverberation decay times thus indicate the amount of time sound ateach frequency sub-band takes to decay a given amount (e.g., 60 dB)within the user environment.

As shown, the frequency sub-bands associated with the reverberationdecay times may include one or more sub-bands in common with thefrequency sub-bands of the environment equalizations and/or one or moresub-bands different than the frequency sub-bands of the environmentequalizations. Additionally, while the above description indicatesspecific sets of frequency sub-bands for the environment equalizationsand the reverberation decay times, the audio rendering system 102 mayuse the neural networks to output predictions at different sets (andnumbers) of frequency sub-bands than described above. Furthermore, theaudio rendering system 102 may determine whether the outputs for one ormore sub-bands are unreliable due to low signal-to-noise ratio, forinstance. Accordingly, in some circumstances, the audio rendering system102 can automatically set environment equalizations or reverberationdecay times for unreliable frequency sub-bands to values of a nearby,reliable sub-band (e.g., setting the reverberation decay time at 62.5 Hzto the same value as the reverberation decay time at 125 Hz).

Accordingly, as shown in the acts 406 and 408, the audio renderingsystem 102 can predict, for a user environment, a plurality ofenvironment equalizations for a first set of frequency sub-bands; andpredict, for the user environment, a plurality of reverberation decaytimes for a second set of frequency sub-bands.

After predicting the reverberation decay times of the user environmentfor a plurality of frequency sub-bands, FIG. 4 illustrates that theseries of acts 400 includes an act 410 of generating an audio simulationmodel for the environment. Specifically, the audio rendering system 102can perform an audio simulation model that simulates the paths of soundbased on the environment geometry for the user environment. Morespecifically, the audio simulation model can use ray tracing techniquesto simulate the paths of the sound by generating a set of sound pathsand then tracking whether each sound path reaches a listener locationand how long each sound path takes to reach the listener location. Theaudio rendering system 102 can take into account how much sound eachsurface absorbs upon reflecting the sound based on the absorptioncoefficients of the materials.

FIG. 4 illustrates that the series of acts 400 also includes an act 412of optimizing material parameters using the audio simulation model. Inparticular, the audio rendering system 102 can optimize absorptioncoefficients of the materials in the user environment, as determinedfrom the audio simulation model, based on the predicted reverberationdecay times from the corresponding neural network. For instance, theaudio rendering system can modify absorption coefficients such that theenergy distributions (e.g., energy curves) of paths in the audiosimulation model match (e.g., are similar to) energy distributions basedon the predicted reverberation decay times. More particularly, the audiorendering system 102 can modify a slope of a given energy curve at afrequency sub-band for the audio simulation model to match a targetslope for an energy curve corresponding to the reverberation decay timeat the same frequency sub-band. Thus, the audio rendering system 102 canensure that the energy decay of the virtualized environment used in theaudio simulation model matches the energy decay of the user environment.FIG. 5 below, and the accompanying description, provide additionaldetail related to the optimization of material parameters.

In connection with optimizing the material parameters, FIG. 4illustrates that the series of acts 400 includes the act 414 ofdetermining materials for the environment from the material parameters.For instance, the audio rendering system 102 can determine a materialfor one or more surfaces or objects based on the optimized materialparameters. According to at least some embodiments, the audio renderingsystem 102 can use a set of initial materials for the audio simulationmodel of the user environment according to the environment geometry. Theaudio rendering system 102 can then update the materials in accordancewith the optimization of the material parameters so that the updatedmaterials have properties that cause the properties of the audiosimulation model to match the properties of the user environment basedon the audio recording. For example, the audio rendering system 102 canset a material of a given surface to be brick, carpet, glass, metal,wood, plastic, etc., based on the determined material parameters for thesurface.

After optimizing the material parameters for the user environment, FIG.4 illustrates that the series of acts 400 includes an act 416 ofgenerating an audio sample using the materials and environmentequalizations. In particular, the audio rendering system 102 can use theacoustic properties and other information that the audio renderingsystem 102 has collected/generated for the user environment to generatean audio sample to present within a virtual/augmented realityenvironment via a client device. To illustrate, the audio renderingsystem 102 can use the determined properties to modify a pre-recordedaudio sample or generate a new audio sample so that the reverberationdecay times and equalizations of the audio sample match thereverberation decay times and equalizations of audio within the userenvironment. For example, the audio rendering system 102 can modify apre-recorded audio sample so that the audio sample has an amplitudewaveform with a decay amplitude and tail shape similar to other audiowithin the user environment. Thus, the resulting audio sample in thevirtual/augmented reality environment can have a similar sound to theother audio originating within the user environment.

In addition to generating an audio sample that has acoustic propertiesthat are based on the acoustic properties of the environment, the audiorendering system 102 can also use information about the environmentgeometry to cause the audio sample to originate at a specific locationwithin the virtualized environment. For instance, in an embodiment inwhich the user environment is a conference room, the audio renderingsystem 102 can generate an audio sample that originates from a virtualcharacter sitting in a chair in an augmented reality environmentcorresponding to the conference room. The audio rendering system 102 canuse virtualization to make the audio sample sound like it's coming froma specific direction and distance from a listener location. The audiorendering system 102 can also make the audio sample sound as if theaudio sample is happening within the conference room such that the audiosample blends with other sounds in the conference room. For example, theaudio rendering system 102 can use the principles described by A.Rungta, C. Schissler, N. Rewkowski, R. Mehra, and D. Manocha inDiffraction kernels for interactive sound propagation in dynamicenvironments, IEEE transactions on visualization and computer graphics,24(4):1613-1622, 2018, or H. Yeh, R. Mehra, Z. Ren, L. Antani, D.Manocha, and M. Lin in Wave-ray coupling for interactive soundpropagation in large complex scenes, ACM Transactions on Graphics (TOG),32(6):165, 2013, which are hereby incorporated in their entirety, toplace audio samples at specific locations within virtual environmentsand accurately propagate the sound through the virtual environments.

In another example, the audio rendering system 102 can analyze videorecorded in an environment to determine acoustics for the environment.In particular, the audio rendering system 102 can analyze noisy,reverberant audio from the video to determine the acoustic properties ofthe environment including environment equalizations and reverberationdecay times for sets of frequency sub-bands. Additionally, the audiorendering system 102 can estimate an environment geometry from thevideo. The audio rendering system 102 can then simulate sound that issimilar to the recorded sound in the environment of the video and addthe sound to the video. Thus, the audio rendering system 102 cansimulate sound for an environment even without direct access to theenvironment.

As mentioned briefly above, the audio rendering system 102 can optimizematerial properties for a user environment based on an audio simulationmodel and predicted reverberation decay times for the user environment.FIG. 5 illustrates graph diagrams of energy curves associated with anaudio simulation model for a user environment. In particular, FIG. 5illustrates energy curves at different frequency sub-bands before andafter optimization of the material parameters.

For example, FIG. 5 illustrates simulation energy curves correspondingto a first frequency sub-band. As shown, the first frequency sub-bandcorresponds to a sub-band centered at 125 Hz. FIG. 5 illustrates a firstsimulation energy curve 500 a corresponding to an unoptimized energycurve from an audio simulation model for a user environment.Additionally, FIG. 5 illustrates a target slope 502 corresponding to anenergy curve based on a reverberation decay time for the userenvironment.

In one or more embodiments, the audio rendering system 102 optimizes thematerial parameters for the user environment at the first frequencysub-band by adjusting a slop of the first simulation energy curve 500 ato match a target slope 502. This results in a second simulation energycurve 500 b that has a slope matching the target slope 502. Modifyingthe slope of the first simulation energy curve 500 a to create thesecond simulation energy curve 500 b by modifying the materialparameters causes the second simulation energy curve 500 b to have decaysimilar to an energy decay of the user environment.

As noted previously, the audio rendering system 102 can perform materialoptimization for each of a plurality of frequency sub-bandsindependently from each other. Accordingly, FIG. 5 also illustratessimulation energy curves 504 a, 504 b and a target slope 506 for asecond frequency sub-band centered at 8000 Hz. Because the userenvironment associated with FIG. 5 causes different effects on sound atthe first frequency sub-band centered at 125 Hz and at the secondfrequency sub-band centered at 8000 Hz, the energy curves for the userenvironment based on the reverberation decay times at those frequencysub-bands are different. In particular, FIG. 5 illustrates that thereverberation decay time is shorter at the 8000 Hz sub-band than at the125 Hz sub-band. Accordingly, the audio rendering system 102 may need tomodify the corresponding energy curves for the audio simulation modeldifferent amounts at each frequency sub-band.

In one or more embodiments, the audio rendering system 102 performs theoptimization of materials using an objective function that allows theaudio rendering system 102 to efficiently optimize the materialparameters. Indeed, as mentioned above, the audio rendering system 102can utilize an objective function that reduces a difference between afirst slope of an audio simulation energy curve (determined based on theaudio simulation model) and a second slope of a reverberation energycurve based on a predicted reverberation decay time. In one or moreembodiments, for example, the audio rendering system 102 can generate anaudio simulation model by first generating a set of sound paths, each ofwhich carries an amount of sound energy. Additionally, each materialm_(i) in a scene can be represented by a frequency dependent absorptioncoefficient ρ_(i). The audio simulation model can simulate that a set ofmaterials can reflect a sound path leaving a source before reaching alistener. The energy fraction received by the listener along path j is

e _(j)=β_(j)Π_(k=1) ^(N) ^(j) ρ_(m) ^(k).

where m^(k) is the material the path intersects on the k^(th) bounce,N_(j) is the number of surface reflections for path j, and β_(j)accounts for air absorption (dependent on the total length of the path).The audio rendering system 102 can optimize the set of absorptioncoefficients ρ₁ to match the energy distribution of the paths e_(j) tothat of the environments impulse response (as reconstructed based on thepredicted reverberation decay times and environment equalizations). Inone or more embodiments, the audio rendering system may assume theenergy decrease of the impulse response follows an exponential curve,which is a linear decay in the dB space. The slope of the decay line ism′=−60/T₆₀ where T₆₀ is the reverberation decay time for the energy todecay 60 dB.

In one or more embodiments, the audio rendering system 102 uses anobjective function

J(ρ)=(m−m′)²

where m is the best fit line of the ray energies on a decibel scale:

$m = \frac{{n{\sum_{i = 0}^{n}{t_{i}y_{i}}}} - {\sum_{i = 0}^{n}{t_{i}{\sum_{i = 0}^{n}y_{i}}}}}{{n\Sigma_{i = 0}^{n}t_{i}^{2}} - \left( {\Sigma_{i = 0}^{n}t_{i}} \right)^{2}}$

with y_(i)=10 log₁₀(e_(i)). In particular, the audio rendering system102 can use the objective function to focus on the energy decrease ofaudio based on the material properties. For example, the audio renderingsystem 102 can allow the absolute scale of the values from an audiosimulation move while optimizing only the slope of the best fit line ofthe ray energies. This can result in a better match to the target slopeof the reverberation decay time for the frequency sub-band. In one ormore embodiments, the audio rendering system 102 also minimizes J usingan optimization algorithm (e.g., limited-memoryBroyden-Fletcher-Goldfarb-Shanno-B or “L-BFGS-B” algorithm).Furthermore, a gradient of J can be represented by

${\frac{\partial J}{\partial\rho_{j}} = {2\left( {m - m^{\prime}} \right)\frac{{n\; t_{i}} - {\sum_{i = 0}^{n}t_{i}}}{{n{\sum_{i = 0}^{n}t_{i}^{2}}} - \left( {\sum_{i = 0}^{n}t_{i}} \right)^{2}}}}\frac{10}{10\log_{10}}\frac{\partial e_{i}}{\partial\rho_{j}}$

As described in relation to FIGS. 4 and 5, the audio rendering system102 can perform operations for analyzing an audio recording using neuralnetworks to predict acoustic properties for a user environment. Theoperations allow the audio rendering system 102 to accurately simulateaudio within a virtualization of the user environment and then generateaudio samples that have characteristics reflecting the acousticproperties of the user environment. Accordingly, the acts and operationsillustrated and described above in relation to FIGS. 3-5 5 can providethe corresponding acts (e.g., structure) for a step for utilizing aneural network and an audio simulation model to predict an environmentequalization, a reverberation decay time, and environment materialparameters from the audio recording.

As described previously, the audio rendering system 102 can also trainneural networks to predict acoustic properties of a user environmentfrom simple audio recordings. Additionally, the audio rendering system102 can augment a training dataset (or a validation dataset) based onthe acoustic properties of measured impulse responses to increase theutility of the training dataset. FIG. 6 illustrates a diagram detailinga series of acts 600 for augmenting a training dataset by generatingsynthetic impulse responses using information about individual sub-bandsof measured impulse responses. In particular, FIG. 6 illustrates thatthe audio rendering system 102 can use equalization data from aplurality of impulse responses to augment a training dataset.

As illustrated in FIG. 6, the series of acts 600 includes an act 602 ofidentifying measured impulse responses. Specifically, the audiorendering system 102 can access one or more sets of impulse responsesthat have been captured within a variety of environments usingspecialized equipment and environment configurations. Because suchdatasets tend to be small, however, the audio rendering system 102 canaugment the training dataset with synthetic data to increase the datapoints that the audio rendering system 102 can use in training neuralnetworks. For instance, in one or more embodiments, the audio renderingsystem 102 uses impulse responses and speech data from ACE Challengeimpulse responses (i.e., 70 impulse responses and noise audio), MIT IRsurvey (271 impulse responses), and DAPS dataset (4.5 hours of 20speakers' speech—10 males and 10 females) to train a reverberationconvolutional neural network and an equalization convolutional neuralnetwork.

In addition to identifying measured impulse responses, FIG. 6illustrates that the series of acts 600 includes an act 604 ofgenerating synthetic impulse responses to augment the training dataset.In particular, because of the limited size of the dataset(s) of measuredimpulse responses, the audio rendering system 102 can perform an initialaugmentation of generating synthetic impulse responses. For example, theaudio rendering system 102 can expand the reverberation decay times anddirect-to-reverberant ratio range of a set of measured impulseresponses, resulting in a large number of synthetic impulse responseswith a balanced reverberation decay time distribution (e.g., between0.1˜0.5 seconds), as described by N. J. Bryan in Impulse response dataaugmentation and deep neural networks for blind room acoustic parameterestimation. arXiv preprint arXiv:1909.03642 (2019), which isincorporated by reference herein in its entirety. The audio renderingsystem 102 can compute ground truth reverberation decay time estimatesdirectly from measured impulse responses in a variety of ways (e.g.,according to the methods described in M. Karjalainen, P. Antsalo, A.Makivirta, T. Peltonen, and V. Valimaki. Estimation of model decayparameters from noisy response measurements. In Audio EngineeringSociety Convention 110. Audio Engineering Society, 2001).

In one or more embodiments, the audio rendering system 102 augments theequalizations of the training dataset(s) using information aboutequalizations of the measured impulse responses. FIG. 6 illustrates thatthe series of acts 600 includes an act 606 of fitting equalizations ofmeasured impulse responses to normal distributions. More specifically,the audio rendering system 102 can analyze equalizations within eachfrequency sub-band (e.g., by extracting the original equalizations ofthe measured impulse responses) to determine mean and standard deviationof impulse response equalization amplitudes/gains within each sub-band.For instance, FIG. 8A below illustrates an example of fittingequalization gains to normal distributions according to a set offrequency sub-bands.

Once the audio rendering system 102 has fit the equalization gains ofthe impulse responses to normal distributions, FIG. 6 illustrates thatthe series of acts 600 includes an act 608 of sampling equalizationsfrom the normal distributions. For example, the audio rendering system102 can randomly sample a target equalization corresponding to afrequency sub-band from the normal distribution at the frequencysub-band. The audio rendering system 102 can also randomly sample targetequalizations from each of the other normal distributions independentlyper frequency sub-band to obtain a plurality of sampled targetequalization across the plurality of sub-bands. To illustrate, byrandomly sampling from each sub-band independently, the audio renderingsystem 102 can obtain a plurality of equalizations that correspond todifferent measured impulse responses across the different frequencysub-bands.

FIG. 6 also illustrates that the series of acts 600 includes an act 610of comparing the sampled equalizations to equalizations of the syntheticimpulse responses. In particular, the audio rendering system 102 cancalculate, for each of a plurality of synthetic impulse responses, adistance between the source equalizations (equalizations correspondingto a given synthetic impulse response) and the target equalizations(randomly sampled equalizations). For instance, the audio renderingsystem 102 can calculate a distance between an equalization of asynthetic impulse response at a first frequency sub-band (e.g., 4000 Hz)and a randomly sampled equalization at the first frequency sub-band.

Once the audio rendering system 102 has compared the source and targetequalizations, FIG. 6 illustrates that the series of acts 600 includesan act 612 of creating filters based on the differences inequalizations. Specifically, for a given synthetic impulse response, theaudio rendering system 102 can create a filter based on the differencebetween the synthetic impulse response and the corresponding randomlysampled equalizations at a plurality of frequency sub-bands.Additionally, in one or more embodiments, the audio rendering system 102generates a finite impulse response filter (“FIR filter”) to compensatefor the calculated difference. According to one or more embodiments, theaudio rendering system 102 can use a window method for designing thefilter to simplify the creation of the filter. The audio renderingsystem 102 can likewise generate a filter for each of the syntheticimpulse responses compared to randomly sampled equalizations.

FIG. 6 illustrates that the series of acts 600 also includes an act 614of generating new synthetic impulse responses using the filters. Forexample, the audio rendering system 102 can apply a generated filter toa synthetic impulse response to create a new impulse response based onthe difference between the synthetic impulse response and the randomlysampled equalizations. Applying the filters to the synthetic impulseresponses provides an efficient way to extend the training dataset whilealso causing the new synthetic impulse responses to have properties thatare similar to the properties of the measured impulse responses. FIGS.8B-8C and the accompanying description provide additional detail withregard to generating new synthetic impulse responses based on measuredimpulse responses.

In some embodiments, the audio rendering system 102 computes the logMel-frequency spectrogram for a plurality of four second audio clips.The audio rendering system 102 can utilize a Hann window of size 256with 50% overlap during computation of a short-time Fourier transform(STFT) four 16 kHz samples. Then, the audio rendering system 102 canutilize 32 Mel-scale bands and area normalization for Mel-frequencywarping (the spectrogram power computed in decibels). This extractionprocess yields a 32×499 (frequency×time domain) matrix featurerepresentation. The audio rendering system 102 can normalize the featurematrices by the mean and standard deviation of the training set.

Optionally, the audio rendering system 102 can establish certainparameters for randomly sampling the equalizations for comparing to thesynthetic impulse responses. To illustrate, the audio rendering system102 can intentionally sample equalizations so that the new syntheticimpulse responses have different statistical distributions than themeasured impulse responses. For example, the audio rendering system 102can increase the variance in the normal distributions of measuredimpulse response. By using a larger variance, the audio rendering system102 can increase the variety of training data, which can improvetraining of the neural networks to account for additional scenarios thatare not included in small training datasets of measured impulseresponses.

To illustrate, the audio rendering system 102 can determine a normaldistribution having an initial variance (e.g., an initial standarddeviation from a mean). The audio rendering system can generate amodified normal distribution by increasing the initial variance to atarget variance. For instance, the audio rendering system can modify theinitial standard deviation to a larger, target standard deviation,resulting in a modified normal distribution. The audio rendering system102 can then sample equalizations from the modified normal distributionto generate a set of equalizations with a larger variance.

Upon generating synthetic impulse responses, the audio rendering system102 can utilize the synthetic impulse responses to train a neuralnetwork. Indeed, the audio rendering system 102 utilize the syntheticimpulse responses in combination with audio recordings to generatetraining recordings (e.g., speech audio recordings) that reflectparticular environment equalizations and reverberation decay rates.

FIG. 7 illustrates an embodiment of a neural network structure 700 thatthe audio rendering system 102 can use to predict acoustic properties ofa user environment based on an audio recording input. As shown, theaudio rendering system 102 can use the same neural network structure 700for each of the neural networks that the audio rendering system 102utilizes to predict environment equalizations and reverberation decaytimes. In particular, the audio rendering system 102 can train twoseparate neural networks having the neural network structure 700 withthe exception of the final output layer, which is dependent on thespecific set of frequency sub-bands corresponding to each acousticproperty. To illustrate, the audio rendering system 102 can use a firstconvolutional neural network having the neural network structure 700with a first output layer 702 based on the specific set of frequencysub-bands for environment equalizations (e.g., six outputs from 62.5 Hzto 4000 Hz sub-bands and excluding a 1 kHz sub-band). The audiorendering system 102 can also use a second convolutional neural networkhaving the neural network structure 700 with a second output layer 704based on the set of frequency sub-bands for reverberation decay times(e.g., seven outputs from 125 Hz to 8000 Hz sub-bands and including a 1kHz sub-band).

The audio rendering system 102 can utilize a variety of neural networkarchitectures in relation to the neural networking structure 700. Toillustrate, in relation to the embodiment of FIG. 7, the audio renderingsystem 102 utilizes six 2D convolutional layers sequentially to reduceboth time and frequency resolution of features until they haveapproximately the same dimension. Each convolutional layer is followedby a rectified linear unit (ReLU) activation function, 2D max pooling,and batch normalization. The output from the convolutional layers isflatted to a 1D vector and connected to a fully connected layer of 64units, at a dropout rate of 50% to lower the risk of overfitting. Thefinal output layer has 7 fully connected units to predict a vector oflength 7 for T60 or 6 fully connected units to predict a vector oflength 6 for frequency equalization. The audio rendering system 102 canutilize different layers, dropout rates, or other architectural featuresin different embodiments.

The audio rendering system 102 can also train a neural network (such asthe neural network architecture 700). In particular, the audio renderingsystem 102 can utilize training data sets (such as the augmentedtraining data described in relation to FIG. 6) to train the neuralnetwork. Specifically, the audio rendering system 102 can access orgenerate training audio recordings from training impulse responses(e.g., generate training speech recordings by convolving speechrecordings with training impulse responses). The audio rendering system102 can feed the training audio recordings to the neural network. Theneural network can analyze the training audio recordings and generatepredicted environment equalizations and/or predicted reverberation decayrates.

The audio rendering system 102 can train the neural network by comparingthe predicted environment equalizations and/or predicted reverberationdecay rates with ground truth measurements (e.g., ground truthequalizations and/or ground truth reverberation decay rates from thetraining impulse responses). Specifically, the audio rendering system102 can apply a loss function to determine a measure of loss between thepredicted acoustic properties and the ground truth. The audio renderingsystem 102 can then modify internal parameters of the neural networkbased on the measure of loss by utilizing back-propagation techniques.To illustrate, in one or more embodiments, the audio rendering system102 utilizes the mean square error (MSE) loss with an Adam optimizer, asdescribed by D. Kingma, J. Ba in Adam: a method for stochasticoptimization, 3rd International Conference on Learning Representations,ICLR 2015.

FIGS. 8A-8D illustrate equalization data corresponding to measuredimpulse responses and synthetic impulse responses, as described withrespect to FIG. 6. Specifically, FIG. 8A illustrates a plurality ofnormal distributions applied to equalization gains of measured impulseresponses for a plurality of frequency sub-bands. FIG. 8B illustratesequalizations for randomly sampled values from measured impulseresponses (e.g., target impulse responses). FIG. 8C illustratesequalizations for synthetic impulse responses (e.g., source impulseresponses). FIG. 8D illustrates equalizations for new synthetic impulseresponses based on randomly sampled equalizations from the targetimpulse responses relative to the source impulse responses.

As mentioned, FIG. 8A illustrates equalization gains of a plurality ofmeasured impulse responses fitted to normal distributions correspondingto a set of frequency sub-bands 800 a-800 f. For example, the audiorendering system 102 can determine the mean and standard deviation ofequalization gains within a first frequency sub-band 800 a. The audiorendering system 102 can then generate a normal distribution (e.g., aGaussian) that represents the equalization gains for the first frequencysub-band 800 a. The audio rendering system 102 can randomly sample fromeach of the frequency sub-bands 800 a-800 f to obtain a plurality ofrandomly sampled equalization gain values. The audio rendering system102 can use the randomly sampled values to generate a filter that theaudio rendering system 102 can use to generate a new synthetic impulseresponse.

For example, FIG. 8B illustrates target equalizations 802 based onrandomly sampled equalizations from the normal distributions. As shown,the target equalizations 802 include different equalization values forthe set of frequency sub-bands. The audio rendering system 102 cancompare the target equalizations 802 to source equalizations 804, shownin FIG. 8C, which correspond to previously generated synthetic impulseresponses. The audio rendering system 102 can generate filters based onthe differences between the source equalizations 804 and the targetequalizations 802 and then modify the source equalizations 804 using thefilter to create new synthetic equalizations 806, shown in FIG. 8D. AsFIGS. 8B and 8D illustrate, the distribution of the new syntheticequalizations 806 is similar to the distribution of the targetequalizations 802, which indicates that the augmented portion of thetraining dataset can incorporate acoustic information from the measuredimpulse responses, thereby improving the accuracy of the neuralnetworks.

In a specific implementation of the audio rendering system 102, theaudio rendering system 102 provides improvements over conventionalsystems. In particular, as described by D. Li, T. R. Langlois, and C.Zheng in Scene-aware audio for 360° videos, ACM Trans. Graph., 37(4),2018, (“Li”) a previous system introduces scene-aware audio to optimizesimulator parameters to match room acoustics from existing recordings.Also, as described by C. Schissler, C. Loftin, and D. Manocha inAcoustic classification and optimization for multi-modal rendering ofreal-world scenes, IEEE transactions on visualization and computergraphics, 24(3):1246-1259, 2017, (“Schissler”) a previous systemleverages visual information for acoustic material classification toinclude audio for 3D-reconstructed real-world scenes. Both of thesesystems, however, require explicit measurement of impulse responses forthe environments. In contrast, the audio rendering system 102 is able torender scene-aware audio with any speech input signal and commoditymicrophones (e.g., in user client devices such as smartphones).

The table below provides a comparison between the performance of theaudio rendering system 102 and Li with regard to error in equalizationsand reverberation decay times for a plurality of different environments.

1428 990 72 352 1100 (12 × (11 × (4 × (11 × Size (m³) (irregular) 12 ×7) 15 × 6) 6 × 3) 8 × 4) Li T₆₀ error 0.11 0.23 0.08 0.02 0.10 (s) Li EQerror 1.50 2.97 8.59 3.61 7.55 (dB) System 102 0.14 0.12 0.10 0.04 0.24T₆₀ error (s) System 102 2.26 3.86 3.97 3.46 4.62 EQ error (dB)As shown in the table above, the audio rendering system 102 produceserror that is comparable to, or better than, Li, which relies onexplicitly measured impulse responses.

Additionally, in contrast to the system in Schissler, the audiorendering system 102 compensates wave effects explicitly with anequalization filter. This allows the audio rendering system 102 tobetter reproduce fast decay in the high-frequency range to closely matcha recorded sound. Furthermore, the audio rendering system 102 providesadditional advantages over conventional systems by producing audio withdecay tail that better matches the audio recordings. In contrast to someof the conventional systems (e.g., as described by H. Kim, L. Remaggi,P. Jackson, and A. Hilton in Immersive spatial audio reproduction forvr/ar using room acoustic modelling from 360 images, Proceedings IEEEVR2019, 2019), the conventional systems produce a longer reverb tailthan a recorded ground truth.

Additionally, FIG. 9 illustrates results for a listening test presentedto a plurality of participants. Specifically, the participants respondedto a prompt to rate how similar each recording was to an explicitreference. The recordings all had the same content, but differentacoustic conditions. As shown, the audio rendering system 102 producedresults that participants rated better than a mid-anchor stimulus 900 bya statistically significant amount (e.g., ˜10 rating points on a 100point scale). More specifically, the audio rendering system 102 producedbetter results with a stimulus 902 using only the predictedreverberation decay times, as well as with a stimulus 904 using thepredicted reverberation decay times in conjunction with the predictedenvironment equalizations.

As described in relation to FIGS. FIGS. 2-9, the audio rendering system102 can perform operations for scene-aware rendering of audio usingneural networks to predict acoustic properties of a user environment.The operations allow the audio rendering system 102 to efficiently andaccurately render digital audio to have similar acoustic properties toaudio within a user environment. FIG. 10 illustrates a detailedschematic diagram of an embodiment of the audio rendering system 102described above. As shown, the audio rendering system 102 can beimplemented in a virtual environment system 110 on computing device(s)1000 (e.g., a client device and/or server device as described in FIG. 1and as further described below in relation to FIG. 12). Additionally,the audio rendering system 102 can include, but is not limited to, anenvironment geometry manager 1002, an audio recording manager 1004, anaudio simulator 1006, a material optimizer 1008, an audio renderingmanager 1010, and a data storage manager 1012. The audio renderingsystem 102 can be implemented on any number of computing devices. Forexample, the audio rendering system 102 can be implemented in adistributed system of server devices for rendering digital media withinan immersive environment. The audio rendering system 102 can also beimplemented within one or more additional systems. Alternatively, theaudio rendering system 102 can be implemented on a single computingdevice such as a single client device.

In one or more embodiments, each of the components of the audiorendering system 102 is in communication with other components using anysuitable communication technologies. Additionally, the components of theaudio rendering system 102 can be in communication with one or moreother devices including other computing devices of a user, serverdevices (e.g., cloud storage devices), licensing servers, or otherdevices/systems. It will be recognized that although the components ofthe audio rendering system 102 are shown to be separate in FIG. 10, anyof the subcomponents may be combined into fewer components, such as intoa single component, or divided into more components as may serve aparticular implementation. Furthermore, although the components of FIG.10 are described in connection with the audio rendering system 102, atleast some of the components for performing operations in conjunctionwith the audio rendering system 102 described herein may be implementedon other devices within the environment.

The components of the audio rendering system 102 can include software,hardware, or both. For example, the components of the audio renderingsystem 102 can include one or more instructions stored on acomputer-readable storage medium and executable by processors of one ormore computing devices (e.g., the computing device(s) 600). Whenexecuted by the one or more processors, the computer-executableinstructions of the audio rendering system 102 can cause the computingdevice(s) 600 to perform the audio rendering operations describedherein. Alternatively, the components of the audio rendering system 102can include hardware, such as a special purpose processing device toperform a certain function or group of functions. Additionally, oralternatively, the components of the audio rendering system 102 caninclude a combination of computer-executable instructions and hardware.

Furthermore, the components of the audio rendering system 102 performingthe functions described herein with respect to the audio renderingsystem 102 may, for example, be implemented as part of a stand-aloneapplication, as a module of an application, as a plug-in forapplications, as a library function or functions that may be called byother applications, and/or as a cloud-computing model. Thus, thecomponents of the audio rendering system 102 may be implemented as partof a stand-alone application on a personal computing device or a mobiledevice. Alternatively, or additionally, the components of the audiorendering system 102 may be implemented in any application that providesaudio rendering, including, but not limited to ADOBE® AUDITION®, ADOBE®CREATIVE CLOUD® software. “ADOBE,” “ADOBE AUDITION,” and “CREATIVECLOUD” are registered trademarks of Adobe in the United States and/orother countries.

As mentioned, the audio rendering system 102 can include an environmentgeometry manager 1002. The environment geometry manager 1002 canfacilitate obtaining, generating, and managing environment geometriesrepresenting user environments. For example, the environment geometrymanager 1002 can communicate with a user client device or other deviceto obtain a computer representation of a user environment. Theenvironment geometry manager 1002 can also communicate with one or moreother components of the audio rendering system 102 to use theenvironment geometries in rendering scene-aware audio.

The audio rendering system 102 can also include an audio recordingmanager 1004 to facilitate management of audio recordings associatedwith user environments. To illustrate, the audio recording manager 1004can capture audio recordings via a recording application using an audiocapture device within a user environment or from a video clip within theuser environment. The audio recording manager 1004 can alternativelyobtain an audio recording from a separate computing device.

The audio recording manager 1004 can also analyze the audio recordingsusing neural networks to predict acoustic properties of a userenvironment. For instance, the audio recording manager 1004 can analyzean audio recording using a plurality of convolutional neural networks topredict environment equalizations and reverberation decay times of theuser environment at various frequency sub-bands. The audio recordingmanager 1004 can also map the predicted acoustic properties to the audiorecordings and corresponding user environments.

Additionally, the audio rendering system 102 can include an audiosimulator 1006 to facilitate the generation of audio simulation modelsof user environments. Specifically, the audio simulator 1006 can useinformation about a user environment to simulate the propagation ofsound waves within the user environment. For instance, the audiosimulator 1006 can use an environment geometry for an environment toestimate how sound interacts with surfaces in the user environment basedon material properties. The audio simulator 1006 can thus estimateenergies (e.g., amplitudes) of audio originating at a source when theaudio reaches a target.

In connection with the audio simulator 1006, the audio rendering system102 can include a material optimizer 1008 to facilitate the optimizationof material parameters of surface materials in a user environment. Toillustrate, the material optimizer 1008 can optimize material parameters(e.g., material absorption coefficients) for surfaces in a userenvironment by comparing an output of the audio simulator 1006 topredicted acoustic properties of the user environment to determinematerials of the user environment. In particular, the material optimizer1008 can modify material absorption coefficients so that the acousticproperties of a virtualized environment match the acoustic properties ofthe user environment.

Additionally, the audio rendering system 102 includes an audio renderingmanager 1010. The audio rendering manager 1010 facilitates thegeneration of scene-aware audio samples that take into account theacoustic properties of user environments. For example, the audiorendering manager 1010 can use environment equalizations, materialparameters, and environment geometries to generate audio samples thathave similar acoustic properties to other audio within the correspondinguser environments. Additionally, the audio rendering manager 1010 canmodify existing (e.g., pre-recorded) audio samples or live-streamingaudio samples according to the acoustic properties of a userenvironment.

Additionally, the audio rendering system 102 also includes a datastorage manager 1012 (that comprises a non-transitory computermemory/one or more memory devices) that stores and maintains dataassociated with rendering scene-aware audio for user environments. Forexample, the data storage manager 1012 can store information associatedwith the user environments, audio recordings, and virtualizedenvironments corresponding to the user environments. To illustrate, thedata storage manager 1012 can store environment geometries, audiorecordings, material parameters, predicted acoustic properties, andrendered audio samples.

Turning now to FIG. 11, this figure shows a flowchart of a series ofacts 1100 of using neural networks to predict acoustic properties of auser environment based on an audio recording for generating scene-awareaudio samples. While FIG. 11 illustrates acts according to oneembodiment, alternative embodiments may omit, add to, reorder, and/ormodify any of the acts shown in FIG. 11. The acts of FIG. 11 can beperformed as part of a method. Alternatively, a non-transitory computerreadable medium can comprise instructions, that when executed by one ormore processors, cause a computing device to perform the acts of FIG.11. In still further embodiments, a system can perform the acts of FIG.11.

As shown, the series of acts 1100 includes an act 1102 of identifying anaudio recording of an environment and an estimated environment geometryfor the environment. For example, act 1102 involves identifying an audiorecording within a user environment and an estimated environmentgeometry for the user environment. For instance, the audio recording caninclude a speech recording captured by a client device within the userenvironment. Alternatively, act 1102 can include identifying an audioclip from video captured within the user environment.

The series of acts 1100 also includes an act 1104 of predicting anenvironment equalization and a reverberation decay time. For example,act 1104 involves predicting, using a neural network and based on theaudio recording, an environment equalization and a reverberation decaytime for the environment. Act 1104 can involve predicting, for theenvironment, a plurality of environment equalizations for a first set offrequency sub-bands. Additionally, act 1104 can involve predicting, forthe environment, a plurality of reverberation decay times for a secondset of frequency sub-bands.

For example, act 1104 can involve predicting the environmentequalization for the user environment by analyzing the audio recordingutilizing the equalization convolutional neural network. Act 1104 canalso involve predicting the reverberation decay time for the userenvironment by analyzing the audio recording utilizing the reverberationconvolutional neural network. The equalization convolutional neuralnetwork can be trained on a plurality of measured impulse responses fora plurality of environments. The reverberation convolutional neuralnetwork can be trained on the plurality of measured impulse responsesfor the plurality of environments. Additionally, the equalizationconvolutional neural network and the reverberation convolutional neuralnetwork can share a single neural network structure comprising differentoutput layers corresponding to the first set of frequency sub-bands andthe second set of frequency sub-bands.

Act 1104 can also involve predicting, utilizing the equalizationconvolutional neural network, a plurality of frequency-dependentenvironment equalizations corresponding to the environment for a firstset of frequency sub-bands. Act 1104 can further involve predicting,utilizing the reverberation convolutional neural network, a plurality offrequency-dependent reverberation decay times corresponding to theenvironment for a second set of frequency sub-bands.

Additionally, the series of acts 1100 includes an act 1106 ofdetermining environment material parameters. For example, act 1106involves determining environment material parameters corresponding tothe environment utilizing an audio simulation model based on theenvironment geometry and the reverberation decay time for theenvironment. For example, the environment material parameters caninclude frequency-dependent absorption coefficients of materials in theuser environment. Act 1106 can involve applying an objective functionthat reduces a difference between a first slope of an audio simulationenergy curve based on the audio simulation model and a second slope of areverberation energy curve based on the reverberation decay time.

The series of acts 1100 further includes an act 1108 of generating anaudio sample. For example, act 1108 involves generating an audio samplebased on the environment geometry, the environment material parameters,and the environment equalization. Act 1108 can involve modifying anaudio sample according to the environment material parameters and theenvironment equalization at a virtual location within the environmentgeometry. For example, the audio sample can include a pre-recorded audiosample or a live-streaming audio sample. Alternatively, act 1108 caninvolve generating a new audio sample according to the environmentmaterial parameters and the environment equalization at a virtuallocation within the environment geometry.

The series of acts 1100 can also include augmenting a training datasetused to train the neural network by modifying equalizations of aplurality of synthetic impulse responses based on sampled equalizationsof a plurality of measured impulse responses. For example, the series ofacts 1100 can augment the training dataset by determining normaldistributions representing equalization gains of the plurality ofmeasured impulse responses at a set of frequency sub-bands. The seriesof acts 1100 can then include sampling a set of equalizations from thenormal distributions, and applying the set of equalizations from thenormal distributions to the plurality of synthetic impulse responses togenerate new synthetic impulse responses. Alternatively, the series ofacts 1100 can include applying the set of equalizations from the normaldistributions to a set of measured impulse responses to generate newsynthetic impulse responses.

For example, the series of acts 1100 can apply the set of equalizationsfrom the normal distributions to the plurality of synthetic impulseresponses by calculating a difference between a source equalization of asynthetic impulse response from the plurality of synthetic impulseresponses and a target equalization of a sample from the set of normaldistributions. The series of acts 1100 can include generating a filterassociated with the difference between the source equalization and thetarget equalization. The series of acts 1100 can then include applyingthe filter to a synthetic impulse response of the plurality of syntheticimpulse responses.

The series of acts 1100 can include sampling the set of equalizationsfrom the normal distributions by identifying initial variances of thenormal distributions. The series of acts 110 can then include generatingmodified normal distributions by increasing the initial variances to atarget variance, and sampling the set of equalizations from the modifiednormal distributions.

Embodiments of the present disclosure may comprise or utilize a specialpurpose or general-purpose computer including computer hardware, suchas, for example, one or more processors and system memory, as discussedin greater detail below. Embodiments within the scope of the presentdisclosure also include physical and other computer-readable media forcarrying or storing computer-executable instructions and/or datastructures. In particular, one or more of the processes described hereinmay be implemented at least in part as instructions embodied in anon-transitory computer-readable medium and executable by one or morecomputing devices (e.g., any of the media content access devicesdescribed herein). In general, a processor (e.g., a microprocessor)receives instructions, from a non-transitory computer-readable medium,(e.g., a memory, etc.), and executes those instructions, therebyperforming one or more processes, including one or more of the processesdescribed herein.

Computer-readable media can be any available media that can be accessedby a general purpose or special purpose computer system.Computer-readable media that store computer-executable instructions arenon-transitory computer-readable storage media (devices).Computer-readable media that carry computer-executable instructions aretransmission media. Thus, by way of example, and not limitation,embodiments of the disclosure can comprise at least two distinctlydifferent kinds of computer-readable media: non-transitorycomputer-readable storage media (devices) and transmission media.

Non-transitory computer-readable storage media (devices) includes RAM,ROM, EEPROM, CD-ROM, solid state drives (“SSDs”) (e.g., based on RAM),Flash memory, phase-change memory (“PCM”), other types of memory, otheroptical disk storage, magnetic disk storage or other magnetic storagedevices, or any other medium which can be used to store desired programcode means in the form of computer-executable instructions or datastructures and which can be accessed by a general purpose or specialpurpose computer.

A “network” is defined as one or more data links that enable thetransport of electronic data between computer systems and/or modulesand/or other electronic devices. When information is transferred orprovided over a network or another communications connection (eitherhardwired, wireless, or a combination of hardwired or wireless) to acomputer, the computer properly views the connection as a transmissionmedium. Transmissions media can include a network and/or data linkswhich can be used to carry desired program code means in the form ofcomputer-executable instructions or data structures and which can beaccessed by a general purpose or special purpose computer. Combinationsof the above should also be included within the scope ofcomputer-readable media.

Further, upon reaching various computer system components, program codemeans in the form of computer-executable instructions or data structurescan be transferred automatically from transmission media tonon-transitory computer-readable storage media (devices) (or viceversa). For example, computer-executable instructions or data structuresreceived over a network or data link can be buffered in RAM within anetwork interface module (e.g., a “NIC”), and then eventuallytransferred to computer system RAM and/or to less volatile computerstorage media (devices) at a computer system. Thus, it should beunderstood that non-transitory computer-readable storage media (devices)can be included in computer system components that also (or evenprimarily) utilize transmission media.

Computer-executable instructions comprise, for example, instructions anddata which, when executed at a processor, cause a general-purposecomputer, special purpose computer, or special purpose processing deviceto perform a certain function or group of functions. In someembodiments, computer-executable instructions are executed on ageneral-purpose computer to turn the general-purpose computer into aspecial purpose computer implementing elements of the disclosure. Thecomputer executable instructions may be, for example, binaries,intermediate format instructions such as assembly language, or evensource code. Although the subject matter has been described in languagespecific to structural features and/or methodological acts, it is to beunderstood that the subject matter defined in the appended claims is notnecessarily limited to the described features or acts described above.Rather, the described features and acts are disclosed as example formsof implementing the claims.

Those skilled in the art will appreciate that the disclosure may bepracticed in network computing environments with many types of computersystem configurations, including, personal computers, desktop computers,laptop computers, message processors, hand-held devices, multi-processorsystems, microprocessor-based or programmable consumer electronics,network PCs, minicomputers, mainframe computers, mobile telephones,PDAs, tablets, pagers, routers, switches, and the like. The disclosuremay also be practiced in distributed system environments where local andremote computer systems, which are linked (either by hardwired datalinks, wireless data links, or by a combination of hardwired andwireless data links) through a network, both perform tasks. In adistributed system environment, program modules may be located in bothlocal and remote memory storage devices.

Embodiments of the present disclosure can also be implemented in cloudcomputing environments. In this description, “cloud computing” isdefined as a model for enabling on-demand network access to a sharedpool of configurable computing resources. For example, cloud computingcan be employed in the marketplace to offer ubiquitous and convenienton-demand access to the shared pool of configurable computing resources.The shared pool of configurable computing resources can be rapidlyprovisioned via virtualization and released with low management effortor service provider interaction, and then scaled accordingly.

A cloud-computing model can be composed of various characteristics suchas, for example, on-demand self-service, broad network access, resourcepooling, rapid elasticity, measured service, and so forth. Acloud-computing model can also expose various service models, such as,for example, Software as a Service (“SaaS”), Platform as a Service(“PaaS”), and Infrastructure as a Service (“IaaS”). A cloud-computingmodel can also be deployed using different deployment models such asprivate cloud, community cloud, public cloud, hybrid cloud, and soforth. In this description and in the claims, a “cloud-computingenvironment” is an environment in which cloud computing is employed.

FIG. 12 illustrates a block diagram of exemplary computing device 1200that may be configured to perform one or more of the processes describedabove. One will appreciate that one or more computing devices such asthe computing device 1200 may implement the system(s) of FIG. 1. Asshown by FIG. 12, the computing device 1200 can comprise a processor1202, a memory 1204, a storage device 1206, an I/O interface 1208, and acommunication interface 1210, which may be communicatively coupled byway of a communication infrastructure 1212. In certain embodiments, thecomputing device 1200 can include fewer or more components than thoseshown in FIG. 12. Components of the computing device 1200 shown in FIG.12 will now be described in additional detail.

In one or more embodiments, the processor 1202 includes hardware forexecuting instructions, such as those making up a computer program. Asan example, and not by way of limitation, to execute instructions fordynamically modifying workflows, the processor 1202 may retrieve (orfetch) the instructions from an internal register, an internal cache,the memory 1204, or the storage device 1206 and decode and execute them.The memory 1204 may be a volatile or non-volatile memory used forstoring data, metadata, and programs for execution by the processor(s).The storage device 1206 includes storage, such as a hard disk, flashdisk drive, or other digital storage device, for storing data orinstructions for performing the methods described herein.

The I/O interface 1208 allows a user to provide input to, receive outputfrom, and otherwise transfer data to and receive data from computingdevice 1200. The I/O interface 1208 may include a mouse, a keypad or akeyboard, a touch screen, a camera, an optical scanner, networkinterface, modem, other known I/O devices or a combination of such I/Ointerfaces. The I/O interface 1208 may include one or more devices forpresenting output to a user, including, but not limited to, a graphicsengine, a display (e.g., a display screen), one or more output drivers(e.g., display drivers), one or more audio speakers, and one or moreaudio drivers. In certain embodiments, the I/O interface 1208 isconfigured to provide graphical data to a display for presentation to auser. The graphical data may be representative of one or more graphicaluser interfaces and/or any other graphical content as may serve aparticular implementation.

The communication interface 1210 can include hardware, software, orboth. In any event, the communication interface 1210 can provide one ormore interfaces for communication (such as, for example, packet-basedcommunication) between the computing device 1200 and one or more othercomputing devices or networks. As an example, and not by way oflimitation, the communication interface 1210 may include a networkinterface controller (NIC) or network adapter for communicating with anEthernet or other wire-based network or a wireless NIC (WNIC) orwireless adapter for communicating with a wireless network, such as aWI-FI.

Additionally, the communication interface 1210 may facilitatecommunications with various types of wired or wireless networks. Thecommunication interface 1210 may also facilitate communications usingvarious communication protocols. The communication infrastructure 1212may also include hardware, software, or both that couples components ofthe computing device 1200 to each other. For example, the communicationinterface 1210 may use one or more networks and/or protocols to enable aplurality of computing devices connected by a particular infrastructureto communicate with each other to perform one or more aspects of theprocesses described herein. To illustrate, the digital content campaignmanagement process can allow a plurality of devices (e.g., a clientdevice and server devices) to exchange information using variouscommunication networks and protocols for sharing information such aselectronic messages, user interaction information, engagement metrics,or campaign management resources.

In the foregoing specification, the present disclosure has beendescribed with reference to specific exemplary embodiments thereof.Various embodiments and aspects of the present disclosure(s) aredescribed with reference to details discussed herein, and theaccompanying drawings illustrate the various embodiments. Thedescription above and drawings are illustrative of the disclosure andare not to be construed as limiting the disclosure. Numerous specificdetails are described to provide a thorough understanding of variousembodiments of the present disclosure.

The present disclosure may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. For example, the methods described herein may beperformed with less or more steps/acts or the steps/acts may beperformed in differing orders. Additionally, the steps/acts describedherein may be repeated or performed in parallel with one another or inparallel with different instances of the same or similar steps/acts. Thescope of the present application is, therefore, indicated by theappended claims rather than by the foregoing description. All changesthat come within the meaning and range of equivalency of the claims areto be embraced within their scope.

What is claimed is:
 1. A computer-implemented method comprising:determining, by at least one processor, a first energy curve byutilizing an audio simulation model to estimate sound paths within anenvironment according to an environment geometry of the environment anda reverberation decay time of the environment; determining, by the atleast one processor, material parameters of materials within theenvironment based on a difference between the first energy curve and asecond energy curve corresponding to the reverberation decay time of theenvironment; and generating, by the at least one processor, an audiosample based on the environment geometry, the material parameters, andan environment equalization of the environment.
 2. Thecomputer-implemented method as recited in claim 1, wherein determiningthe material parameters of the materials comprises: determining a firstslope of the first energy curve and a second slope of the second energycurve; and reducing a difference between the first slope of the firstenergy curve and the second slope of the second energy curve.
 3. Thecomputer-implemented method as recited in claim 2, wherein reducing thedifference between the first slope of the first energy curve and thesecond slope of the second energy curve comprises modifying absorptioncoefficients associated with the materials to change the first slope ofthe first energy curve.
 4. The computer-implemented method as recited inclaim 1, wherein determining the first energy curve comprisesgenerating, utilizing the audio simulation model, a plurality ofsimulated sound paths reflected by one or more surfaces within theenvironment according to an initial set of materials of the one or moresurfaces.
 5. The computer-implemented method as recited in claim 4,further comprising: determining initial material parameters for theinitial set of materials of the one or more surfaces; determiningmodified material parameters based on the difference between the firstenergy curve and the second energy curve; and determining an updated setof materials for the one or more surfaces within the environmentaccording to the modified material parameters.
 6. Thecomputer-implemented method as recited in claim 4, wherein determiningthe material parameters of the materials within the environmentcomprises utilizing the audio simulation model to determine whether theplurality of simulated sound paths reach a location within theenvironment and how long each estimated sound path takes to reach thelocation according to the environment geometry and the reverberationdecay time.
 7. The computer-implemented method as recited in claim 1,wherein generating the audio sample comprises modifying a pre-recordedaudio sample according to the material parameters and the environmentequalization at a virtual location within the environment geometry. 8.The computer-implemented method as recited in claim 1, furthercomprising determine, utilizing one or more neural networks, theenvironment equalization and the reverberation decay time from an audiorecording within the environment.
 9. The computer-implemented method asrecited in claim 8, wherein determining the environment equalization andthe reverberation decay time comprises: determining, utilizing the oneor more neural networks, a plurality of frequency-dependent environmentequalizations for a first set of frequency sub-bands; and determining,utilizing the one or more neural networks, a plurality offrequency-dependent reverberation decay times for a second set offrequency sub-bands.
 10. A system comprising: one or more memory devicescomprising an environment geometry of an environment; and one or moreprocessors configured to cause the system to: determine a first energycurve by utilizing an audio simulation model to estimate sound pathswithin the environment according to the environment geometry of theenvironment and a reverberation decay time of the environment; determinea second energy curve corresponding to the reverberation decay time ofthe environment; determine material parameters of materials within theenvironment by modifying the first energy curve to reduce a differencebetween the first energy curve and the second energy curve; and generatean audio sample based on the environment geometry, the materialparameters, and an environment equalization of the environment.
 11. Thesystem as recited in claim 10, wherein the one or more processors arefurther configured to cause the system to reduce the difference betweenthe first energy curve and the second energy curve by modifying aninitial set of material parameters to change a slope of the first energycurve based on the difference between the first energy curve and thesecond energy curve.
 12. The system as recited in claim 11, wherein theone or more processors are further configured to cause the system tomodify the initial set of material parameters by modifyingfrequency-based absorption coefficients to change the slope of the firstenergy curve at a particular frequency sub-band to fit a slope of thesecond energy curve at the particular frequency sub-band.
 13. The systemas recited in claim 12, wherein the one or more processors are furtherconfigured to cause the system to determine the second energy curve by:determining, utilizing one or more neural networks, the environmentequalization and the reverberation decay time from an audio recordingwithin the environment; and determining the second energy curve for theparticular frequency sub-band from a plurality of energy curves based onfrequency-dependent reverberation decay times at a plurality offrequency sub-bands.
 14. The system as recited in claim 10, wherein theone or more processors are further configured to cause the system todetermine the first energy curve by utilizing the audio simulation modelto determine whether the estimated sound paths reach a location withinthe environment and how long each estimated sound path takes to reachthe location according to the environment geometry, the reverberationdecay time, and an initial set of materials within the environment. 15.The system as recited in claim 10, wherein the one or more processorsare further configured to cause the system to determine, utilizing oneor more neural networks, the environment equalization and thereverberation decay time from an audio recording within the environmentby: determining, utilizing the one or more neural networks, a pluralityof frequency-dependent environment equalizations for a first set offrequency sub-bands; and determining, utilizing the one or more neuralnetworks, a plurality of frequency-dependent reverberation decay timesfor a second set of frequency sub-bands, the second set of frequencysub-bands being different than the first set of frequency sub-bands. 16.The system as recited in claim 15, wherein the one or more processorsare further configured to cause the system to determine the materialparameters for the materials by determining frequency-dependent materialparameters for a plurality of frequency sub-bands independently fromeach other based on the plurality of frequency-dependent environmentequalizations at the first set of frequency sub-bands and the pluralityof frequency-dependent reverberation decay times at the second set offrequency sub-bands.
 17. A non-transitory computer readable storagemedium comprising instructions that, when executed by at least oneprocessor, cause a computing device to: determine, for an environment,an environment geometry and a reverberation decay time; determine afirst energy curve by utilizing an audio simulation model to estimateinteractions of sound paths with surfaces within the environmentaccording to the environment geometry and the reverberation decay time;determine a second energy curve corresponding to the reverberation decaytime of the environment; determine material parameters of the surfaceswithin the environment by modifying the first energy curve correspondingto the audio simulation model based on the second energy curvecorresponding to the reverberation decay time; and generate an audiosample based on the environment geometry, the material parameters, andan environment equalization of the environment.
 18. The non-transitorycomputer readable storage medium as recited in claim 17, furthercomprising instructions that, when executed by the at least oneprocessor, cause the computing device to: determine the first energycurve by utilizing the audio simulation model with initial materialparameters for the surfaces within the environment; and modify thematerial parameters by updating the initial material parameters toreduce a difference between the first energy curve and the second energycurve.
 19. The non-transitory computer readable storage medium asrecited in claim 17, further comprising instructions that, when executedby the instructions, cause the computing device to: determine theenvironment equalization by determining, utilizing an equalizationconvolutional neural network, a plurality of environment equalizationscorresponding to the environment for a first set of frequency sub-bands;and determine the reverberation decay time by determining, utilizing areverberation decay time convolutional neural network, a plurality ofreverberation decay times corresponding to the environment for a secondset of frequency sub-bands.
 20. The non-transitory computer readablestorage medium as recited in claim 19, further comprising instructionsthat, when executed by the instructions, cause the computing device todetermine the material parameters of the surfaces by modifying a slopeof the first energy curve at a sub-band from both the first set offrequency sub-bands and the second set of frequency sub-bands.